नारद–शुक संवादः
Impermanence, Svabhāva, and Śuka’s Resolve for Yoga
गुणक्षयत्वात् प्रकृति: कर्तृत्वादक्षयं बुधा: । एषा ते<<न्वीक्षिकी विद्या चतुर्थी साम्परायिकी
guṇakṣayatvāt prakṛtiḥ kartṛtvād akṣayaṃ budhāḥ | eṣā te ’nvīkṣikī vidyā caturthī sāmparāyikī ||
Because its qualities (guṇas) are subject to diminution and dissolution, the primordial Nature (prakṛti) is held to be perishable; but because the Person (puruṣa) is the instigator and inner agent, the wise declare him imperishable. O king of the Gandharvas, this is the fourth discipline of inquiry (ānvīkṣikī) that I have taught you—knowledge that bears upon the highest end and supports liberation.
याज़्ञवल्क्य उवाच
The verse distinguishes prakṛti and puruṣa: prakṛti is perishable because it is constituted by guṇas that undergo change and dissolution, while puruṣa is imperishable as the inner principle associated with agency/instigation. This discrimination is presented as ānvīkṣikī—philosophical inquiry—aimed at the highest good (mokṣa).
Yājñavalkya addresses the Gandharva king and concludes a segment of instruction by presenting a doctrinal summary: he has taught a ‘fourth’ ānvīkṣikī vidyā, characterized as sāmparāyikī—knowledge oriented toward the ultimate end and liberation.